Surgical fastener applying apparatus

ABSTRACT

A fastener applying apparatus ( 20 ) includes an anvil half-section ( 100 ) and a cartridge receiving half-section ( 200 ) having a distal portion dimensioned to releasably receive a single use loading unit (“SULU”) ( 400 ) and a proximal portion configured to support a firing assembly ( 500 ). The firing assembly includes a stationary housing ( 502 ) and a firing lever ( 516 ) having one or more lever guide projections ( 522 ). The firing lever is slidable from a proximal end of the stationary housing to a distal end of the stationary housing to define a firing stroke. A clamping lever ( 300 ) is movable from an undamped position to a clamped position to releasably secure the distal anvil portion in close approximation with the SULU. The clamping lever defines one or more lever guide slots ( 316 ). The lever guide projection(s) is positioned to enter the lever guide slot(s) upon initiation of the firing stroke to inhibit movement of the clamping lever to the undamped position during the firing stroke.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical fastener applying apparatusand, more particularly, to a surgical fastener applying apparatus havingreusable and disposable components.

2. Discussion of Related Art

Surgical fastener applying apparatus wherein tissue is first grasped orclamped between opposing jaw structures and then joined with surgicalfasteners, are well known in the art. In some such apparatus, a knife isprovided to cut the tissue which has been joined by the fasteners. Thefasteners are typically in the form of surgical staples, although, othersurgical fasteners may also be utilized, such as, for example, clips ortwo part polymeric surgical fasteners.

Surgical fastener applying apparatus typically include two elongatedbeam members which are used to capture or clamp tissue therebetween.Typically, one of the beam members carries a disposable cartridgeassembly which houses a plurality of staples arranged in at least twolateral rows, while the other beam member includes an anvil whichdefines a surface for forming the staple legs as the staples are drivenfrom the cartridge assembly. Where two part fasteners are used, the beammember which includes the anvil carries a mating part of the two partfastener, e.g. the receiver.

Generally, the staple formation process is affected by the interactionbetween one or more longitudinally moving camming members and a seriesof individual staple pushers. As the camming members travellongitudinally through the cartridge carrying beam member, theindividual pusher members are biased upwardly into a backspan of thestaples supported within the cartridge assembly to sequentially ejectthe staples from the cartridge. A knife may be provided to travel withthe camming members between the staple rows to cut the tissue betweenthe rows of formed staples. An example of such an instrument isdisclosed in U.S. Pat. No. 7,631,794, which is incorporated herein inits entirety by reference.

SUMMARY

The present invention relates to a surgical fastener applying apparatusfor applying surgical fasteners to tissue. In embodiments, the surgicalfastener applying apparatus includes an anvil half-section including adistal anvil portion and a proximal handle portion, and a cartridgereceiving half-section defining an elongated channel member. Theelongated channel member has a distal portion dimensioned to releasablyreceive a single use loading unit and a proximal portion configured tosupport a firing assembly. The firing assembly includes a stationaryhousing and a firing lever having at least one lever guide projectionextending from the firing lever. The firing lever is slidable from aproximal end of the stationary housing to a distal end of the stationaryhousing to define a firing stroke. A clamping lever is secured to thecartridge receiving half-section and includes a proximal handle portion.The clamping lever is operably associated with the anvil half-sectionand the cartridge receiving half-section and is movable from anunclamped position to a clamped position to releasably secure the distalanvil portion of the anvil half-section in close approximation with thesingle use loading unit. The proximal handle portion of the clampinglever defines at least one lever guide slot. The at least one leverguide projection is positioned to enter the at least one lever guideslot upon initiation of the firing stroke to inhibit movement of theclamping lever to the unclamped position during the firing stroke.

In embodiments, the clamping lever is releasably secured to thecartridge receiving half-section.

In embodiments, at least one of the proximal handle portion of the anvilhalf-section and the proximal handle portion of the clamping leverdefines a plurality of apertures to facilitate cleaning andsterilization of the anvil half-section and/or the clamping lever.

In embodiments, the distal anvil portion of the anvil half-sectiondefines a longitudinal slot extending therethrough. The longitudinalslot defines a relatively narrow bottom portion and a top portion thatincreasingly widens in a direction extending away from the bottomportion.

In embodiments, the firing assembly includes a stationary housing havinga bottom surface and a protrusion extending downwardly from the bottomsurface. The proximal portion of the elongated channel member of thecartridge receiving half-section defines an aperture configured toreceive the protrusion of the stationary housing to releasably secureand align the firing assembly within the elongated channel member.

In embodiments, the firing assembly is configured to be releasablysecured within the cartridge receiving half-section prior to releasablysecuring the single use loading unit within the elongated channelmember.

In embodiments, a biasing member is supported in a distal end of thefiring assembly. The biasing member is configured to inhibit fullseating of the single use loading within the elongated channel memberprior to movement of the clamping lever to the clamped position.

In embodiments, the anvil half-section includes a proximally located barand the cartridge receiving half-section includes a pair of proximallylocated support members that each define a vertical slot. The bar isconfigured to be received within the vertical slots to pivotably supportthe anvil half-section in relation to the cartridge receivinghalf-section.

In embodiments, the clamping lever includes a pair of inwardly-extendingprojections and the cartridge receiving half-section defines a pair ofdimples. The projections of the clamping lever are configured to bereceived within the dimples of the cartridge receiving half-section toreleasably retain the clamping lever in an intermediate position betweenthe clamped position and the unclamped position.

In embodiments, the at least one lever guide slot has a mouth. The atleast one lever guide projection is positioned to enter the mouth of theat least one lever guide slot upon movement of the clamping lever to theclamped position.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical fastenerapplying apparatus will now be described herein with reference to theaccompanying figures wherein:

FIG. 1 is a side perspective view of an embodiment of the presentlydisclosed surgical fastener applying apparatus in the clamped position;

FIG. 2 is a side perspective view of the surgical fastener applyingapparatus of FIG. 1 during assembly of the clamping lever and thecartridge receiving half-section;

FIG. 3 is a side perspective view of the surgical fastener applyingapparatus of FIG. 1 shown with parts separated;

FIG. 4A is a side perspective view of the anvil half-section of thesurgical fastener applying apparatus of FIG. 1;

FIG. 4B is a bottom perspective view of the anvil half-section of FIG.4A;

FIG. 5 is a bottom, perspective view of the proximal end portion of theanvil half-section of FIG. 4A;

FIG. 6A is a side view of the proximal end of the anvil half-section andcartridge-receiving half-section of the surgical fastener applyingapparatus of FIG. 1 shown disengaged from one another;

FIG. 6B is a side view of the proximal end of the anvil half-section andcartridge-receiving half-section of FIG. 6A shown engaged to oneanother;

FIG. 7A is a bottom perspective view of the cartridge-receivinghalf-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 7B is a side view of the cartridge-receiving half-section of FIG.7A;

FIG. 8 is an enlarged side perspective view of the area of detailindicated in FIG. 7A;

FIG. 9 is a side perspective view of the firing assembly of the surgicalfastener applying apparatus of FIG. 1;

FIG. 10 is bottom perspective view of the proximal end of the stationaryhousing of the firing assembly of FIG. 9;

FIG. 11A is a longitudinal cross-sectional view of the cartridgereceiving half-section of the surgical fastener applying apparatus ofFIG. 1 with the single use loading unit (“SULU”) partially engagedtherein;

FIG. 11B is a longitudinal cross-sectional view of the cartridgereceiving half-section of FIG. 11A with the SULU fully engaged therein;

FIG. 12A is a bottom perspective view of the distal portion of the anvilhalf-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 12B is a top perspective view of the distal portion of the anvilhalf-section of FIG. 12A;

FIG. 13 is a transverse cross-sectional view taken across section line13-13 of FIG. 12B;

FIG. 14A is a top perspective view of the clamping lever of the surgicalfastener applying apparatus of FIG. 1; and

FIG. 14B is a side view of the clamping lever of FIG. 14A.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed surgical fastener applyingapparatus will now be described in detail with reference to the drawingswherein like reference numerals identify similar or identical structuralelements in each of the several views. As used herein, as istraditional, the term “proximal” refers to the end of the apparatuswhich is closer to the user, while the term distal refers to the end ofthe apparatus which is further away from the user.

FIGS. 1-2 illustrate an embodiment of the presently disclosed surgicalfastener applying apparatus shown generally as surgical stapler 10.Surgical stapler 10 includes an anvil half-section 100, a cartridgereceiving half-section 200, a clamping lever 300, a single use loadingunit 400 (hereinafter “SULU”), and a firing assembly 500. Anvilhalf-section 100, cartridge receiving half-section 200, and clampinglever 300 may be configured as reusable components and, as such, may beconstructed from biocompatible materials suitable for sterilization andrepeated use, e.g., stainless steel. As will be described below, anvilhalf-section 100, cartridge receiving half-section 200 and clampinglever 300 each include features to facilitate effective sterilizationthereof. SULU 400 and firing assembly 500, on the other hand, aredisposable components and are separable from the reusable components ofsurgical stapler 10. SULU 400 and firing assembly 500 may be constructedfrom any suitable biocompatible material including plastics, metals, orcombinations thereof. Further, surgical stapler 10 may be configured toreceive or accommodate SULUs and/or firing assemblies for firing staplesof different staple line lengths, e.g., 60 mm, 80 mm, and 100 mm.

Referring to FIGS. 4A-4B and 12A-13, anvil half-section 100 includes aproximal handle portion 102 and a distal anvil portion 104. Distal anvilportion 104 includes a staple deforming portion 106 (FIG. 4B) whichincludes a plurality of staple deforming recesses 108 (FIG. 12B) definedwithin bottom surface 110 thereof. Staple deforming portion 106 can beformed integrally with anvil half-section 100, or in the alternative,secured to anvil half-section 100 by a fastening process such aswelding, tacking, or crimping, or other adhesive. Bottom surface 110 ofdistal anvil portion 104, which defines staple deforming portion 106, isconfigured to face a top surface of SULU 400 (FIG. 3) when SULU 400(FIG. 3) is positioned in channel member 202 of cartridge receivinghalf-section 200 (see FIG. 2). Distal anvil portion 104 defines acentral longitudinal slot 112 (FIGS. 12A-13) which extends along asubstantial portion of the length of anvil portion 104. As best shown inFIGS. 12A-13, central longitudinal slot 112 has a relatively-narrowbottom portion 114 that extends through bottom surface 110 of stapledeforming portion 106 for slidably receiving knife 406 of SULU 400 (seeFIG. 3) as knife 406 is moved through SULU 400 (see FIG. 3) to cuttissue between the lateral rows 115 of staples (FIG. 12B). As shown inFIG. 13, top portion 116 of central longitudinal slot 112 graduallywidens from bottom portion 114 to top surface 118 of distal anvilportion 104, wherein central longitudinal slot 112 defines a relativelywide opening. By providing a central longitudinal slot 112 that widensas shown, less material is required to form the distal anvil portion104, thereby reducing the weight of the distal anvil portion 104. Inaddition, the widened slot 112 allows for more effective cleaning andsterilization of the distal anvil portion 104.

With reference to FIGS. 1-5, and to FIGS. 4A-4B in particular, a centralportion 120 of anvil half-section 100 is defined between the proximalend of staple deforming portion 106 of distal anvil portion 104 and thedistal end of proximal handle portion 102 of anvil half-section 100.Central portion 120 of anvil half-section 100 includes two pairs ofcylindrical lateral support members 124, 126. Central portion 120 ofanvil half-section further includes at least one protrusion such as apair of support fingers 125 extending downwardly towards cartridgereceiving half-section 200. During assembly of anvil half-section 100and cartridge receiving half-section 200, lateral support members 124function to set the minimum gap between SULU 400 (FIG. 3) and stapledeforming portion 106 of anvil half-section 100 when surgical stapler 10(FIG. 1) is in the clamped position. Lateral support members 126, on theother hand, are supported in U-shaped recesses 212 defined in centralportion 210 of cartridge receiving half-section 200 (see FIGS. 7A-7B) toproperly align SULU 400 (FIG. 3) relative to staple deforming portion106 of anvil half-section 100 when surgical stapler 10 (FIG. 1) is inthe clamped position. Further, in the clamped position, lateral supportmembers 126 are received in cutouts 310 formed on spaced flange portions308 of clamping lever 300. As stapler 10 is moved to the clampedposition, support fingers 125 urge SULU 400 (FIG. 3) fully into positionwithin channel member 202 of cartridge receiving half-section 200.

With continued reference to FIGS. 4A-4B in particular, proximal handleportion 102 of anvil half-section 100 is ergonomically formed andincludes a body portion 128 and a thumb-engaging abutment 130. Bodyportion 128 may define a plurality of apertures 132 that facilitate thecleaning and sterilization of proximal handle portion 102. The provisionof apertures 132 in body portion 128 also reduces the overall weight ofsurgical stapler 10.

With additional reference to FIG. 5, a proximal end of proximal handleportion 102 includes a downwardly extending protrusion, finger 134 whichdefines a rear locator bar 136 which will be discussed in further detailbelow (FIGS. 6A-6B). Rear locator bar 136 may assume a variety ofconfigurations, e.g., cylindrical, tear-drop shaped, etc. Rear locatorbar 136 may include at least one projection extending laterallytherefrom. As best shown in FIG. 5, bar 136 may be integrated with,e.g., monolithically formed with, proximal handle portion 102 of anvilhalf-section 100 towards the proximal end thereof.

Referring to FIGS. 7A-8, cartridge receiving half-section 200 defines anelongated channel member 202 which defines a substantially U-shapedchannel 204 having a distal portion 206 dimensioned to releasablyreceive SULU 400 (FIG. 3) and a proximal portion 208 dimensioned toreleasably receive firing assembly 500 (FIG. 9). Cartridge receivinghalf-section 200 further includes a central portion 210 defining spacedU-shaped recesses 212 which are positioned to support lateral supportmembers 126 of anvil half-section 100 (see FIGS. 1-3), as mentionedabove. Central portion 210 of cartridge receiving half-section 200further includes a pair of downwardly extending fingers 214 positionedbeneath recesses 212. Fingers 214 each support a cylindrical pivotmember 216 which is configured to be received within a respectiveC-shaped recesses 314 of a spaced flange portion 308 of clamping lever300 to facilitate clamping of surgical stapler 10 (see FIGS. 1-3), aswill be described below. Each one of a pair of dimples 218 definedwithin central portion 210 of cartridge receiving half-section 200 isconfigured to receive a projection 312 of clamping lever 300 toreleasably secure clamping lever 300 (see FIGS. 1-3) in an intermediateposition, between the clamped and unclamped positions, as will bedescribed below.

With additional reference to FIGS. 1-3, base surface 220 of proximalportion 208 of elongated channel member 202 defines an elongatelongitudinal slot 222 that is configured to permit passage of biasingmember 506 (FIG. 3), e.g., a flat spring, of firing assembly 500, aswill be described below, to bias clamping lever 300 towards theunclamped position. Positioning biasing member 506 (FIG. 3) on thedisposable firing assembly 500, rather than on the reusable cartridgereceiving half-section 200 or clamping lever 300 obviates the need tosterilize in and around the biasing member 506 (FIG. 3) after use. Inother words, neither cartridge receiving half-section 200 nor clampinglever 300 need include complex features configured to retain biasingmember 506 (FIG. 3) therein and, thus, are easily sterilized. Basesurface 220 of elongated channel member 202 further defines a proximallylocated aperture 224 that is configured to receive a protrusion 504(FIG. 10) which extends outwardly from a bottom surface of stationaryhousing 502 of firing assembly 500 to secure and align firing assembly500 within elongated channel member 202, as will be described below.

With reference to FIGS. 6A-6B, the proximal end of cartridge receivinghalf-section 200 includes a pair of vertical support members 226. Eachvertical support member 226 defines an elongated vertical slot 228 whichmay have a rounded bottom surface, although other configurations arecontemplated. Vertical slots 228 are each dimensioned to receive rearlocator bar 136 of finger 134, which is integral with and extends fromthe proximal end of anvil half-section 100, as mentioned above. Duringassembly, rear locator bar 136 is inserted into each of the verticalslots 228 to pivotably support anvil half-section 100 on cartridgereceiving half-section 200 and axially locate cartridge receivinghalf-section 200 in relation to anvil half-section 100. With positioningbar 136 supported within vertical slots 228 of support member 226, anvilhalf-section 100 can be pivoted in a scissor-like manner with respect tothe cartridge receiving half-section 200 between open and closedpositions.

Referring to FIGS. 1-3 and 7A-10, firing assembly 500 includesstationary housing 502 having a proximal end including a protrusion 504(FIG. 10). As discussed above, the protrusion 504 extends from thebottom surface of the stationary housing 502 and is configured forreceipt within aperture 224 defined within base surface 220 of elongatedchannel member 202 to releasably secure and align the proximal end offiring assembly 500 within proximal portion 208 of elongated channelmember 202. Likewise, SULU 400 (FIG. 3) includes a pair of distalprotrusions 414 (FIG. 3) which are positionable within cutouts 230formed at the distal end of channel member 202 to releasably secure thedistal end of SULU 400 within the distal portion 206 of channel member202. As will be described in further detail below with reference toFIGS. 11A-11B, stationary housing 502 of firing assembly 500 includes abiasing member 526 which is positioned to inhibit the proximal end ofSULU 400 from fully seating within channel member 202 during assembly,thereby serving as a lockout to inhibit accidental firing of firingassembly 500. The proximal end of SULU 400 is only moved into properoperational position within channel member 202 upon clamping of stapler10, wherein sufficient force is provided on SULU 400 to fully seat SULU400 within channel member 202 against the bias of biasing member 526, aswill be discussed in further detail below.

Referring to FIG. 9, stationary housing 502 of firing assembly 500 isconfigured to house the working components of firing assembly 500. Forpurposes herein, it suffices to say that stationary housing 502generally supports a knife actuating bar 508, a cam bar 510, a guideblock 512, a slide block 514, a firing lever 516, as well as otherinter-cooperating components (not explicitly shown) that function tosequentially fire a plurality of surgical fasteners from SULU 400 (FIG.3) and to advance knife 406 (FIG. 3) through SULU 400 (FIG. 3) tosubsequently divide tissue between the lateral rows 115 (FIG. 12B) ofstaples upon actuation of firing lever 516. A more detailed descriptionof a firing assembly similar to firing assembly 500 can be found in U.S.Pat. No. 7,631,794 (“the '794 Patent”), which is incorporated herein byreference in its entirety.

Firing lever 516 of firing assembly 500 includes first and second fingerengagement members 518 and 520, either one of which can be selectivelyengaged to move the firing lever 516 through a firing stroke from eitherside of stapler 10. Firing assembly 500 is configured such that firinglever 516 must first be pivoted to one side or the other of firingassembly 500 before firing lever 516 can be moved through a firingstroke. A lever guide projection 522 extends from a bottom surface ofeach engagement member 518, 520. With additional reference to FIGS. 1-3and 14A-14B, each lever guide projection 522 is configured anddimensioned for receipt within a respective lever guide slot 316 definedon each side of clamping lever 300 upon actuation of firing lever 516,i.e., upon initiation of the firing stroke. As will be described below,the appropriate lever guide slot 316 of clamping lever 300 receives thecorresponding lever guide projection 522 of firing lever 516 (dependingon which side firing lever 516 is pivoted to prior to firing) to bothguide translation of firing lever 516 and to inhibit unclamping ofclamping lever 300 once the firing stroke has been initiated, i.e., oncefiring lever 516 has been moved distally from a fully retractedposition. As used herein, a firing stroke is defined as movement offiring lever 516 from the fully retracted position to a fully advancedposition, while initiation of the firing stroke is defined as themovement of firing lever 516 sufficiently so as to position one of thelever guide projections 522 within the respective lever guide slot 316.

Referring again to FIGS. 1-3, SULU 400 includes a body 402 housing aplurality of staple pushers (not shown), a bottom cover 404, a knife 406having an angled sharpened leading edge or blade (not shown), aplurality of staples (not shown) operably disposed within body 402, anda pivotally mounted safety lockout 408 (FIGS. 11A-11B), which isdescribed in greater detail in the '794 Patent, previously incorporatedherein by reference. Body 402 has a plurality of rows of stapleretaining slots 410, e.g., four, six, etc. and a linear slotted knifetrack 412 centrally disposed in body 402. Surgical stapler 10 can bedimensioned to receive or accommodate SULU's of different staple linelengths including, e.g., 60 mm, 80 mm and 100 mm. Knife 406 may includea downturned hook portion (not shown) which is configured to engageupturned hook portion 524 (FIG. 11A) of knife actuating bar 508 offiring assembly 500, as also described in the '794 Patent. Withreference in particualr to FIGS. 11A-11B, as mentioned above, a biasingmember 526 is supported in a distal end of stationary housing 502 offiring assembly 500 (FIG. 9). Biasing member 526 is positioned andconfigured to inhibit the proximal end of SULU 400 from fully seatingwithin channel member 202 during assembly to inhibit accidental firingof firing assembly 500. More specifically, biasing member 526 preventsSULU 400 from fully seating in channel member 202 until stapler 10 ismoved to a clamped position to prevent the firing assembly 500 (FIG. 9)from operably engaging SULU 400. The proximal end of SULU 400 is onlymoved into the fully seated position within channel member 202 uponclamping of stapler 10, at which time the downturned hook portion (notshown) of knife 406 is operably positioned for engagement with upturnedhook portion 524 (FIG. 11A) of knife actuating bar 508 (FIG. 9). Duringa firing stroke, cam bar 510 (FIG. 9) is slidably movable through body402 to eject staples from SULU 400. Concurrently, but after a presetdelay, knife 406 is advanced through SULU 400 via advancement of knifeactuating bar 508 (FIG. 9) to divide tissue between the lateral rows 115of staples. A more detailed description of a SULU similar to SULU 400can be found in the '794 Patent.

Referring now to FIGS. 14A-14B, in conjunction with FIGS. 1-3, clampinglever 300 includes a handle portion 302 including a grip 304 and a thumbengaging abutment 306. As mentioned above, a pair of spaced flangeportions 308 are supported on the distal end of clamping lever 300. Eachflange portion 308 defines a cutout 310 dimensioned to receive arespective lateral support member 126 of anvil half-section 100 tofacilitate movement of surgical stapler 10 from an unclamped position tothe clamped position (FIG. 1). Flange portions 308 each further includean inwardly-extending projection 312 configured to be received withindimples 218 defined within central portion 210 of cartridge receivinghalf-section 200 in snap-fit fashion upon pivoting of clamping lever 300towards the clamped position to releasably secure clamping lever 300 inan intermediate position between the clamped and unclamped positions.

As discussed above, each flange portion 308 also defines a C-shapedrecess 314 that is configured to receive cylindrical pivot member 216 ofcartridge receiving half-section 200 to permit pivoting of clampinglever 300 relative to cartridge receiving half-section 200 between theunclamped and clamped positions. Clamping lever 300 is fully removableor separable from cartridge receiving half-section 200 by removingflange portions 308 of clamping lever 300 from about cylindrical pivotmembers 216 of cartridge receiving half-section 200. This configurationallows for greater access to both clamping lever 300 and cartridgereceiving half-section 200 and eliminates difficult-to-reach areas ofboth components, thereby facilitating the cleaning and sterilization ofboth components.

With continued reference to FIGS. 14A-14B, handle portion 302 ofclamping lever 300, as also discussed above, includes a longitudinallever guide slot 316 which extends along each side thereof. Lever guideslots 316 each define an opening, or mouth 318 configured to receive thelever guide projection 312 of a corresponding finger engagement member518, 520. More specifically, upon initiation of the firing stroke, thelever guide projection 522 moves from within mouth 518 into thecorresponding lever guide slot 316. When the lever guide projection 522is disposed within the lever guide slot 316, unclamping of clampinglever 300 is inhibited.

Handle portion 302 of clamping lever 300 further defines a plurality ofapertures 320 that facilitate cleaning and sterilization of clampinglever 300 and reduce the overall weight of surgical stapler 10. Biasingmember 506 (FIG. 3), which extends downwardly from firing assembly 500through slot 222 (FIG. 7A) defined within cartridge receivinghalf-section 200, is configured to engage the inner surface of clampinglever 300 to bias clamping lever 300 towards the unclamped position.

Turning now to FIGS. 1-3, in conjunction with FIGS. 4A-14B, the assemblyand operation of stapler 10 is described. Initially, firing assembly500, followed by SULU 400, are loaded into cartridge receivinghalf-section 200. In order to load firing assembly 500 into proximalportion 208 of channel member 202 of cartridge receiving half-section200, stationary housing 502 of firing assembly 500 is inserted intochannel member 202 such that protrusion 504 (FIG. 10), which extendsdownwardly from stationary housing 502 of firing assembly 500 (see FIG.10), is positioned within aperture 224 defined within base surface 220of channel member 202. Once firing assembly 500 is loaded into channelmember 202, SULU 400 can be loaded into distal portion 206 of channelmember 202 via the engagement of distal protrusions 414 within cutouts230. However, as noted above, at this point, the proximal end of SULU400 will only partially seat within channel member 202 of cartridgereceiving half-section 200 due to the bias of biasing member 526 (FIGS.11A-11B), which urges the proximal end of SULU 400 from channel member202.

Once SULU 400 and firing assembly 500 are loaded into channel member202, anvil half-section 100 can be assembled to cartridge receivinghalf-section 200 by inserting bar 136 into vertical slots 228 ofvertical support members 226 of cartridge receiving half-section 200(see FIGS. 6A-6B). Thereafter, anvil half-section 100 may be rotateddownwardly towards cartridge receiving half-section 200 to positionlateral supports members 126 (FIGS. 4A-4B) in substantially U-shapedrecesses 212 (FIG. 7B).

With anvil half-section 100 and cartridge receiving half-section 200pivotably engaged to one another, clamping lever 300 may be engaged tocartridge receiving half-section 200. Referring to FIGS. 2-3 and14A-14B, to engage clamping lever 300 to cartridge receivinghalf-section 200, flange portions 308 of clamping lever 300 areapproximated about central portion 210 of cartridge receivinghalf-section 200 such that cylindrical pivot members 216 (FIG. 3) ofcartridge receiving half-section 200 are inserted into substantiallyC-shaped recesses 314 of clamping lever 300. Thereafter, clamping lever300 may be rotated in a counter-clockwise direction (according to theorientation shown in FIG. 2) about pivot member 216 (FIG. 3) andrelative to cartridge receiving half-section 200 to the intermediateposition. In the intermediate position, projections 312 (FIG. 14B) arereceived within apertures or dimples 218 (FIG. 3) to retain clampinglever 300 in the intermediate position relative to cartridge receivinghalf-section 200.

In use, in order grasp tissue between anvil half-section 100 and SULU400, surgical stapler 10 is positioned such that tissue to be grasped isdisposed between anvil half-section 100 and SULU 400. Thereafter,clamping lever 300 is rotated in the counter-clockwise direction fromthe intermediate position to the clamped position shown in FIG. 1 toapproximate staple deforming portion 106 of anvil half-section 100 andtop surface of SULU 400 to grasp tissue therebetween. As clamping lever300 is rotated towards the clamped position, lateral support members 126are received in cutouts 310 (FIG. 2) of flange portions 308 of clampinglever 300 and support fingers 125 engage SULU 400 to urge SULU 400downwardly to be fully seated within channel member 202 of cartridgereceiving half-section 200 against the bias of biasing member 526 (FIGS.11A-11B). When SULU 400 is fully seated in channel member 202, SULU 400is moved into operative engagement with firing assembly 500 such thatknife actuating bar 508 and knife 406 are operably engaged to oneanother to permit actuation of firing assembly 500.

With surgical stapler 10 in the clamped, unfired position, firing lever516 is pivoted to either side of stapler 10 to facilitate actuation ofsurgical stapler 10 from either side of the stapler 10. With firinglever 516 pivoted to the desired side of stapler 10, the correspondinglever guide projection 522 of the finger engagement member 518, 520 offiring lever 516 is positioned within the corresponding mouth 318 of aguide slot 316 of clamping lever 300 (FIG. 1). In this position, stapler10 may still be unclamped, but is ready for firing.

In order to fire stapler 10, the finger engagement member 518, 520 offiring lever 516 is advanced distally along channel member 202, in thedirection indicated by arrow “A” in FIG. 1. Upon initial distaladvancement of the finger engagement member 518, 520, the lever guideprojection 522 is moved from mouth 318 of a respective slot 316 ofclamping lever 300 into the lever guide slot 316 to inhibit unclampingof clamping lever 300 during the firing stroke and to guide translationof firing lever 516 through the firing stroke. As firing lever 516 isadvanced distally, slide block 514 is moved distally within stationaryhousing 502 of firing assembly 500 to effect corresponding movement ofcam bar 510 and delayed movement of knife actuating bar 508. As cam bar510 is moved distally through stationary housing 502 of firing assembly500 and into SULU 400, the cam surfaces of cam bar 510 sequentiallyengage the pushers (not explicitly shown) disposed within SULU 400 toeject the staples (not explicitly shown) from body 402, through tissue,and into staple deforming portion 106 of anvil half-section 100 forforming the staples about tissue. Concurrently, since the distal end ofknife actuating bar 508 is engaged with knife 406, knife 406, after thepreset delay, is advanced through SULU 400 to incise tissue between thelateral rows 115 (FIG. 12B) of staples (not shown).

When firing lever 516 is returned to its proximal-most position toretract cam bar 510 and knife 406 after completion of the firing stroke,lever guide projection 522 is moved from lever guide slot 316 back tomouth 318 of the respective slot 316, thus permitting clamping lever 300to move back to the intermediate position. Thereafter, clamping lever300 may be disengaged and removed from cartridge receiving half-section200 and stapler 10 may be moved to the open position to release thestapled and divided tissue. In the open position, anvil half-section 100is spaced from cartridge receiving half-section 200 such that biasingmember 526 (FIGS. 11A-11B) urges the proximal end of SULU 400 from afully-seated position within channel member 202, thereby facilitatingthe removal of SULU 400 from channel member 202.

During a surgical procedure, SULU 400 can be replaced multiple times tofacilitate multiple uses of stapler 10 on a single patient. For example,during a surgical procedure to remove a diseased portion of a vesselfrom the vessel, the surgical stapler 10 can be used to staple and cuttissue on opposite sides of the diseased vessel portion. The SULU 400can be replaced after each staple and cut operation of the surgicalstapler 10. Since each SULU 400 is provided with a fresh knife 406,tearing of tissue is minimized. After the surgical procedure, the usedSULU(S) 400 and firing assembly 500 can be removed from channel member202 and disposed of in an appropriate manner. The anvil half-section100, cartridge receiving half-section 200 and clamping lever 300, asmentioned above, can then be sterilized, such as by autoclaving, andreused with a new SULU 400 and firing assembly 500 in the mannerdiscussed above.

It will be understood that various modifications may be made to theembodiments of the surgical fastener applying apparatus disclosedherein. Therefore, the above description should not be construed aslimiting, but merely as exemplifications of embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the present disclosure.

What is claimed is:
 1. A surgical fastener applying apparatuscomprising: an anvil half-section including a distal anvil portion and aproximal handle portion; a cartridge receiving half-section defining anelongated channel member, the elongated channel member having a distalportion dimensioned to releasably receive a single use loading unit anda proximal portion configured to support a firing assembly, the firingassembly including a stationary housing and a firing lever having atleast one lever guide projection extending from the firing lever, thefiring lever being slidable from a proximal end of the stationaryhousing to a distal end of the stationary housing to define a firingstroke; and a clamping lever secured to the cartridge receivinghalf-section and including a proximal handle portion, the clamping leverbeing operably associated with the anvil half-section and the cartridgereceiving half-section and being movable from an unclamped position to aclamped position to releasably secure the distal anvil portion of theanvil half-section in close approximation with the single use loadingunit, the proximal handle portion of the clamping lever defining atleast one lever guide slot, wherein the at least one lever guideprojection is positioned to enter the at least one lever guide slot uponinitiation of the firing stroke to inhibit movement of the clampinglever to the unclamped position during the firing stroke.
 2. Thesurgical fastener applying apparatus according to claim 1, wherein theclamping lever is releasably secured to the cartridge receivinghalf-section.
 3. The surgical fastener applying apparatus according toclaim 1, wherein at least one of the proximal handle portion of theanvil half-section and the proximal handle portion of the clamping leverdefines a plurality of apertures to facilitate cleaning andsterilization of the anvil half-section and/or the clamping lever. 4.The surgical fastener applying apparatus according to claim 1, whereinthe distal anvil portion of the anvil half-section defines alongitudinal slot extending therethrough, the longitudinal slot defininga relatively narrow bottom portion and a top portion that increasinglywidens in a direction extending away from the bottom portion.
 5. Thesurgical fastener applying apparatus according to claim 1, wherein thefiring assembly includes a stationary housing having a bottom surfaceand a protrusion extending downwardly from the bottom surface whereinthe proximal portion of the elongated channel member of the cartridgereceiving half-section defines an aperture configured to receive theprotrusion of the stationary housing to releasably secure and align thefiring assembly within the elongated channel member.
 6. The surgicalfastener applying apparatus according to claim 1, wherein the firingassembly is configured to be releasably secured within the cartridgereceiving half-section prior to releasably securing the single useloading unit within the elongated channel member.
 7. The surgicalfastener applying apparatus according to claim 6, further including abiasing member supported in a distal end of the firing assembly, thebiasing member being configured to inhibit full seating of the singleuse loading within the elongated channel member prior to movement of theclamping lever to the clamped position.
 8. The surgical fastenerapplying apparatus according to claim 1, wherein the anvil half-sectionincludes a proximally located bar and the cartridge receivinghalf-section includes a pair of proximally located support members thateach define a vertical slot, the bar being configured to be receivedwithin the vertical slots to pivotably support the anvil half-section inrelation to the cartridge receiving half-section.
 9. The surgicalfastener applying apparatus according to claim 1, wherein the clampinglever includes a pair of inwardly-extending projections and wherein thecartridge receiving half-section defines a pair of dimples, theprojections of the clamping lever being configured to be received withinthe dimples of the cartridge receiving half-section to releasably retainthe clamping lever in an intermediate position between the clampedposition and the unclamped position.
 10. The surgical fastener applyingapparatus according to claim 1, wherein the at least one lever guideslot has a mouth and wherein the at least one lever guide projection ispositioned to enter the mouth of the at least one lever guide slot uponmovement of the clamping lever to the clamped position.